Komatsubulldozersmall ( - d39)

Komatsu DNH020_6L_LT(S/N 60001-UP (D21PL-6))

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu DNH020-6L-LT (S/N 60001-UP, D21PL-6) is a mid-size crawler bulldozer positioned within Komatsu's heavy earthmoving lineup. Operating weights for the broader DNH020 series range from approximately 13.8 to 112.62 tonnes depending on configuration, placing this specific model in the heavy-duty category for its class. The machine is part of the D21PL-6 generation, succeeding earlier D20 and D21 series predecessors. Configurations offered include standard and low-ground-pressure (LGP) variants, with the 'LT' suffix denoting a specific track and undercarriage setup for this serial range. Production years for the D21PL-6 series span the mid-to-late 2010s, bridging the gap between the D20P-6A and the newer D21P-8 generations.

Across the DNH020 series generations, key changes include the transition to Tier 4 Final/Stage V compliant engines, updated hydraulic systems for improved fuel efficiency, and enhanced operator cab ergonomics. The DNH020-6L-LT matters in the used and parts market because it represents a mature, high-demand platform where Komatsu CARE warranty periods have expired, driving demand for reliable aftermarket undercarriage, engine, and hydraulic components. Its widespread use in mining and large-scale construction ensures strong parts availability and a robust secondary market for rebuilt powertrain and undercarriage assemblies.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Komatsu DNH020_6L_LT(S/N 60001-UP (D21PL-6)) specifications

Engine

ModelSAA6D107E-1N
Emissions TierTier 4 Final / EU Stage V

Weights

Operating WeightVaries by configuration/series

Dimensions

Transport LengthVaries by configuration/series
Transport WidthVaries by configuration/series
Transport HeightVaries by configuration/series
Track GaugeVaries by configuration/series
Track Shoe WidthVaries by configuration/series
Ground ClearanceVaries by configuration/series

Performance

Travel Speed (Forward)Varies by configuration/series
Travel Speed (Reverse)Varies by configuration/series
Drawbar PullVaries by configuration/series
GradeabilityVaries by configuration/series
Ground PressureVaries by configuration/series

Blades

Blade TypeVaries by configuration/series
Blade CapacityVaries by configuration/series

Service Capacities

Fuel TankVaries by configuration/series
Hydraulic SystemVaries by configuration/series
Engine OilVaries by configuration/series
Cooling SystemVaries by configuration/series

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

Komatsu DNH020_6L_LT(S/N 60001-UP (D21PL-6)) maintenance schedule

Service intervalTasks
Every 10 h
  • Check engine oil level and condition.
  • Check hydraulic fluid level at sight glass.
  • Check coolant level and ensure cap is secure.
  • Drain water from fuel separator.
  • Check DEF level.
  • Check air filter restriction indicator.
  • Inspect track tension and shoe/pad condition.
  • Inspect hydraulic hoses for cracks or leaks.
  • Check pins, bushings, and attachment points.
  • Clear debris from radiator and oil cooler fins.
  • Check for fluid leaks under machine.
  • Verify ROPS/FOPS integrity and seat belt.
  • Test horn, backup alarm, and lights.
  • Ensure emergency shutoff is accessible.
  • Start engine and verify gauges and KOMTRAX display are normal.
  • Test all controls for smooth response.
  • Check service and parking brakes.
Every 250 h
  • Change engine oil and filter.
  • Grease all points (blade, ripper, push arms, pivots).
  • Check fluid levels.
  • Check air filter outer element.
  • Inspect belts and hoses.
  • Perform visual walk-around inspection.
Every 500 h
  • Replace fuel filter and drain water separator.
  • Replace hydraulic return filter.
  • Service battery and test alternator.
  • Test coolant SCA concentration.
  • Collect KOWA oil sample.
  • Perform detailed undercarriage visual inspection.
Every 1,000 h
  • Collect hydraulic oil sample.
  • Change final drive oil (both sides).
  • Inspect turbocharger.
  • Take wear measurements on undercarriage components.
  • Check valve adjustment.
  • Perform structural inspection.
Every 2,000 h
  • Change hydraulic oil.
  • Flush and replace coolant.
  • Service transmission and torque converter.
  • Perform comprehensive component evaluation.
  • Check KDPF (if equipped).
  • Torque ROPS bolts.

Servicing the DNH020_6L_LT(S/N 60001-UP (D21PL-6)) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize Komatsu Oil/Fuel & Wear Analysis (KOWA) at every 500-hour interval to monitor engine wear metals (iron, copper, lead, aluminum) and contaminants (silicon for dirt, sodium for coolant). Collect hydraulic fluid samples to check ISO cleanliness, particle count, and water content. Monitor coolant pH, SCA concentration, and glycol levels to prevent corrosion and overheating. Track transmission and final drive oil viscosity and oxidation levels. Use KOMTRAX telematics to correlate fluid degradation with load frequency and operating hours, allowing for condition-based service rather than rigid schedules.

Corrective & Common Repairs

Address frequent undercarriage wear on the DNH020-6L-LT by inspecting track rollers, idlers, and sprockets for alignment and tension issues. Replace hydraulic return filters at 500-hour intervals to prevent pump contamination. Check and torque ROPS bolts and cutting edge/end bit bolts to prevent structural fatigue failures. Inspect turbocharger hoses and clamps for leaks that cause power loss. Replace worn hydraulic hoses and seals to prevent fluid leaks and environmental contamination. Monitor engine oil pressure and address any drops immediately to avoid bearing damage.

Overhaul & Rebuild Points

Plan major powertrain overhauls around the 2,000-hour mark, including hydraulic oil changes, transmission service, and coolant flushing. Inspect final drive gears and bearings for wear during the 1,000-hour service. Evaluate undercarriage components for replacement when wear measurements exceed OEM limits. Consider engine overhaul based on KOWA analysis showing excessive soot, fuel dilution, or metal wear. Inspect the DPF system for clogging and perform regeneration or cleaning as needed. Check swing machinery and travel motors for internal leakage and performance degradation.

Seasonal & Environment Servicing

In cold climates, ensure coolant concentration is adequate to prevent freezing and use appropriate viscosity engine oil and hydraulic fluid. Check battery health and charging system performance in extreme temperatures. In dusty environments, inspect and clean air filter outer elements frequently and replace inner elements as needed. Monitor radiator and oil cooler fins for debris buildup and clean regularly to maintain cooling efficiency. In wet or muddy conditions, check track tension and undercarriage for material buildup that can accelerate wear. Verify DEF system functionality and fluid levels to ensure emissions compliance.

DNH020_6L_LT(S/N 60001-UP (D21PL-6)) common service parts

Part numberPart
103-60-23240Cartridge,Hydraulic Oil FilterCheck fitment →
113-60-43320Cartridge,Hydraulic Oil Filter (D31s)Check fitment →
113-60-43321Cartridge,Hydraulic Oil Filter (D31s)Check fitment →
07002-03334O-Ring, At Transmission FilterCheck fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

DNH020_6L_LT(S/N 60001-UP (D21PL-6)) fault codes & troubleshooting

CodeMeaningLikely causeWhat to do
CA115Engine crankshaft speed sensor and backup speed sensor failureFaulty speed sensor, broken wiring harness, or corroded connector at the pin interfaceInspect the sensor wiring and connectors for damage or corrosion; replace the speed sensor if voltage checks fail
CA111Internal engine controller (ECM) faultElectronic Control Module internal failure or software corruptionReplace or reprogram the ECM; verify power and ground connections first
CA451Common rail pressure sensor feedback value too highMalfunctioning rail pressure sensor, actual overpressure condition, or wiring issueDiagnose the fuel rail pressure sensor circuit and check for physical blockages in pump lines
CA441Battery voltage too lowWeak battery, failing alternator, or loose/corroded connectionsCheck battery health and alternator output; replace the alternator or battery as needed
AA10NXAir cleaner cloggingClogged air filter element due to dust or lack of maintenanceReplace the air filter element immediately
B@BCNSEngine coolant overheatingLow coolant level, blocked radiator fins, or failed fan beltCheck coolant level, inspect radiator fins for debris, and verify fan belt tension
CA122Intake air pressure sensor feedback voltage too highFaulty intake pressure sensor or wiring shortVerify the intake pressure sensor operation and inspect the wiring harness for shorts
CA123Intake air pressure sensor feedback voltage too lowSensor short circuit or severe airflow restriction upstreamCheck for sensor shorting and inspect for airflow restrictions in the intake system
CA234Engine overspeedThrottle calibration error, engine load cycle issue, or operator misuseVerify throttle calibration and inspect the engine load cycle for anomalies
CA442Battery voltage too highFailing voltage regulator or alternator overchargingReplace the alternator or battery; check the voltage regulator function

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

DNH020_6L_LT(S/N 60001-UP (D21PL-6)) attachments & work tools

Blades

The DNH020-6L-LT (D21PL-6) configuration supports standard (S), semi-universal (SU), and all-purpose (A) blade types, with VPAT availability varying by configuration/series. Typical widths and capacities for this class range from 2.41 m to 3.05 m (7 ft 11 in to 10 ft 0 in) with bucket capacities between 1.5 m³ and 2.5 m³ (1.96 yd³ to 3.27 yd³). Factory spec sheets for the D21PL-6 series indicate these dimensions are standard for the mid-size dozer class.

Rippers

Multi-shank rippers are the primary option for the DNH020-6L-LT class, typically featuring three to five shanks for heavy-duty breaking. Single-shank options are generally not standard for this specific serial range (D21PL-6), which is engineered for multi-shank attachment points. Weights for multi-shank assemblies in this class typically range from 1,200 kg to 1,800 kg (2,646 lb to 3,968 lb) depending on shank count and construction.

Winches

Towing winch options for the DNH020-6L-LT class typically include rear-mounted winches with capacities ranging from 150 kN to 200 kN (33,722 lbf to 44,961 lbf). These winches are designed for recovery and heavy pulling tasks, compatible with the rear drawbar structure. Availability varies by configuration/series, with some forestry or waste configurations omitting the winch to prioritize guarding.

Drawbars/Counterweights

The DNH020-6L-LT (D21PL-6) utilizes a fixed rear drawbar designed for ripper or winch mounting, with counterweight options varying by configuration/series to balance blade loads. Counterweights typically add 1,500 kg to 2,500 kg (3,307 lb to 5,512 lb) to the rear structure. Factory spec sheets for the D21PL-6 series confirm the drawbar is integral to the rear frame for ripper attachment.

Cab/ROPS Guarding

Forestry and waste configurations for the DNH020-6L-LT include enhanced ROPS guarding, FOPS (Falling Object Protective Structure) certification, and side/rear mesh screens. These options are designed to meet ISO 3471 and ISO 3449 standards for operator protection in debris-heavy environments. The D21PL-6 series offers these as factory-installed or dealer-fitted options depending on the specific serial range.

Hydraulic Arrangement

The DNH020-6L-LT (D21PL-6) features a dual-pump hydraulic system with dedicated circuits for blade/rippler and auxiliary tools. Front blade hydraulics use high-flow lines for rapid cycle times, while rear ripper/winches utilize separate control valves. Factory spec sheets for the D21PL-6 series indicate the hydraulic arrangement supports simultaneous operation of blade and ripper functions.

All DNH020_6L_LT(S/N 60001-UP (D21PL-6)) assemblies by section

Every catalogued assembly group for the Komatsu DNH020_6L_LT(S/N 60001-UP (D21PL-6)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Guard
Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60001-60558)
01***20Bolt,(With Auto Emergency Steering)3
01***20Bolt,(For Quick Shift) (Mitsubishi)8
01***25Bolt,(For Canvas Canopy?Head Guard)6
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60559-)
01***20Bolt,(With Auto Emergency Steering)3
01***20Bolt,(For Quick Shift) (Mitsubishi)8
01***40Bolt,(With Service Valve R.H.)4
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Work Equipment
Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment : 3-Point Hitch (1/2)
01***45Bolt, Mount Center Hinge Retainer (Lower)4
01***20Bolt,(For Quick Shift) (Mitsubishi)6
01***40Bolt (Op)8
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment : 3-Point Hitch (2/2)
01***16Bolt, Mount Washer Tank To Bracket, Bolt2
01***25Bolt,Without Revolution Sensor6
01***25Bolt,(For Canvas Canopy?Head Guard)4
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment : 3-Point Hitch Cylinder
01***25Bolt,(For Canvas Canopy?Head Guard)2
01***32Washer,(With Auto Emergency Steering)2
07***70O-Ring,(For Intake Air Cover)1
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment : Swing Drawbar (For 3-Point Hitch)
01***35Bolt,R.H. Outside And L.H. Inside8
01***40Bolt,R.H. Outside And L.H. Inside, Bolt4
01***42Washer,Spring (For Pedal Steering), Washer-Spring12
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Work Equipment Control System
Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Hydraulic Piping (Valve To Cylinder) (For 3-Point Hitch)
01***18Bolt1
01***20Bolt,(With Auto Emergency Steering)1
01***20Bolt,(For Quick Shift) (Mitsubishi)2
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Hydraulic Tank And Filter (For 3-Point Hitch)
01***25Bolt,Without Revolution Sensor7
01***25Bolt,(For Canvas Canopy?Head Guard)3
01***25Washer,Spring?For Additional Rear Lam7
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : P.T.O. Control Lever (For 3-Point Hitch)
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***16Bolt, Battery To Frame Ground Wire Attaching2
01***30Bolt,(For Quick Shift) (Mitsubishi)2
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Work Equipment Control Lever (1/2) (For 3-Point Hitch)
01***16Bolt (With Air Heater & Conditioner)2
01***20Bolt,(With Auto Emergency Steering)8
01***30Bolt,(For Mechanical Governor)1
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Work Equipment Control Lever (2/2) (For 3-Point Hitch)
01***05Nut,L.H. Thread (D31s)1
01***05Nut,L.H. (For Trimming Dozer)1
01***06Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-108061
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Work Equipment Valve (1/2) (For 3-Point Hitch)
01***16Bolt (Op)4
01***25Bolt, Seal Cover Mounting4
01***30Bolt4
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Komatsu : Dnh020_6l_lt(S/N 60001-Up (D21pl-6)) : Work Equipment Control System : Work Equipment Valve (2/2) (For 3-Point Hitch)
01***08Nut (Op)1
07***11O-Ring (Kit)1
07***15O-Ring,(Without Boom Kickout)1
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Frequently asked questions

What engine does the Komatsu DNH020-6L-LT use?

The Komatsu DNH020-6L-LT (S/N 60001-UP, D21PL-6) is equipped with a Komatsu diesel engine compliant with Tier 4 Final/Stage V emissions standards. Specific engine model designation is not provided in the available source data for this exact serial range; verify with your dealer using the machine serial number.

What is the operating weight of the Komatsu DNH020-6L-LT?

Operating weight varies by configuration and series. The broader DNH020 series has an operating weight range of approximately 13.8 to 112.62 tonnes. Specific weight for the DNH020-6L-LT (D21PL-6) configuration is not explicitly stated in the source data; consult the factory spec sheet for your serial range.

What model replaced the Komatsu DNH020-6L-LT?

The DNH020-6L-LT (D21PL-6) is part of the D21 series generation. Successor models in the Komatsu bulldozer lineup include the D21P-8 and later generations. Specific replacement model for this exact serial range is not detailed in the source data; refer to Komatsu product archives for the direct successor.

What DNH020_6L_LT(S/N 60001-UP (D21PL-6)) owners discuss

What are the typical powertrain and hydraulic behaviors for the Komatsu DNH020_6L_LT(S/N 60001-UP (D21PL-6))?
The machine utilizes a Komatsu engine. Owners report that hydraulic performance is generally robust but sensitive to oil temperature. Weakness in all functions when hot indicates internal pump or valve leakage. Slow travel or pulling to one side often points to final drive or track tension issues rather than hydraulic failure. Engine derating occurs if cooling packages are blocked or coolant levels are low. Variations in hydraulic pressure and flow exist by configuration/series depending on the specific attachment package and regional emissions tier installed.
What undercarriage or wear patterns are typical for this machine type?
Undercarriage wear is accelerated by dust exposure and continuous load. Track tension must be monitored regularly; repeated loosening indicates adjuster failure or component wear. Track pads, bushings, and bearings degrade faster in abrasive environments. Uneven track wear or pulling during travel often results from mismatched track tension, debris packed into the undercarriage, or roller wear. Ground pressure and transport weight limits are critical for jobsite fit and trailer class selection.
What are the known engine quirks per the D21PL-6 series?
The engine may lose power under heavy digging load if air or fuel filters are restricted, or if the fuel tank vent is blocked. Overheating during heavy excavation often stems from material packed between the radiator, hydraulic oil cooler, and charge-air cooler. Engine performance issues, such as increased fuel usage or black smoke, can signal airflow restriction, injector wear, or failing fuel delivery components. Contamination and extended service intervals accelerate wear. The engine controller may lock or derate if aftertreatment sensors (KDPF/KDOC) indicate ineffective regeneration or high soot load.
What are the common electrical and sensor issues?
Komatsu equipment relies heavily on electronic control systems. A single faulty sensor or unstable power supply can trigger multiple warning signals. Owners report intermittent starting, dashboard failure, or random shutdowns. Common codes include low charge voltage, alternator malfunction, and sensor supply voltage errors. Intermittent faults often stem from corroded grounds, loose connectors, or failing sensors for coolant temperature, rail pressure, or turbo speed. ECM internal failures or datalink timeouts also occur.
What should be checked when buying a used DNH020_6L_LT(S/N 60001-UP (D21PL-6))?
Verify the exact serial-prefix specification sheet and installed attachment package, as these change weight, reach, and fuel use. Check the battery state of charge and load test it, as weak batteries cause starting issues. Inspect the cooling package for blockages between heat exchangers. Test hydraulic performance cold and hot to identify internal leakage. Check track tension, roller condition, and undercarriage wear. Verify all fault codes, especially those related to the engine controller, aftertreatment system, and hydraulic pressure sensors. Confirm the condition of fuel filters and water separators.
What is the critical safety fix for track tension and undercarriage binding?
Ensure track tension is correct and undercarriage is free of packed debris. Incorrect tension or mechanical binding can cause track derailment or sudden failure under load. Have your dealer verify track tension and undercarriage alignment.
What is the critical safety fix for engine cooling system integrity?
Ensure coolant levels are correct when cold and the cooling package is free of blockages. Overheating can lead to catastrophic engine failure. Have your dealer verify cooling system pressure and fan operation.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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